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Report dlsym, dlvsym lookup errors using dlerror [BZ #19509]

	* elf/dl-lookup.c (_dl_lookup_symbol_x): Report error even if
	skip_map != NULL.
	* elf/tst-dlsym-error.c: New file.
	* elf/Makefile (tests): Add tst-dlsym-error.
	(tst-dlsym-error): Link against libdl.
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Florian Weimer
Florian Weimer committed Mar 31, 2016
1 parent 258ec8a commit 7d45c163d00c88d5875a112343c4ea3e61349e6b
Showing with 125 additions and 2 deletions.
  1. +9 −0 ChangeLog
  2. +3 −1 elf/Makefile
  3. +0 −1 elf/dl-lookup.c
  4. +113 −0 elf/tst-dlsym-error.c
@@ -1,3 +1,12 @@
2016-03-31 Florian Weimer <fweimer@redhat.com>

[BZ #19509]
* elf/dl-lookup.c (_dl_lookup_symbol_x): Report error even if
skip_map != NULL.
* elf/tst-dlsym-error.c: New file.
* elf/Makefile (tests): Add tst-dlsym-error.
(tst-dlsym-error): Link against libdl.

2016-03-29 Joseph Myers <joseph@codesourcery.com>

* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
@@ -149,7 +149,7 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \
tst-nodelete) \
tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \
tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened \
tst-nodelete2 tst-audit11 tst-audit12
tst-nodelete2 tst-audit11 tst-audit12 tst-dlsym-error
# reldep9
ifeq ($(build-hardcoded-path-in-tests),yes)
tests += tst-dlopen-aout
@@ -1257,3 +1257,5 @@ $(objpfx)tst-prelink-cmp.out: tst-prelink.exp \
$(objpfx)tst-ldconfig-X.out : tst-ldconfig-X.sh $(objpfx)ldconfig
$(SHELL) $< '$(common-objpfx)' '$(test-wrapper)' '$(test-wrapper-env)' > $@; \
$(evaluate-test)

$(objpfx)tst-dlsym-error: $(libdl)
@@ -858,7 +858,6 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
if (__glibc_unlikely (current_value.s == NULL))
{
if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
&& skip_map == NULL
&& !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED))
{
/* We could find no value for a strong reference. */
@@ -0,0 +1,113 @@
/* Test error reporting for dlsym, dlvsym failures.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */

#include <dlfcn.h>
#include <gnu/lib-names.h>
#include <stdio.h>
#include <stdlib.h>

/* Used to disambiguate symbol names. */
static int counter;

static void
test_one (void *handle, const char *name, void *(func) (void *, const char *),
const char *suffix)
{
++counter;
char symbol[32];
snprintf (symbol, sizeof (symbol), "no_such_symbol_%d", counter);
char *expected_message;
if (asprintf (&expected_message, ": undefined symbol: %s%s",
symbol, suffix) < 0)
{
printf ("error: asprintf: %m\n");
abort ();
}

void *addr = func (handle, symbol);
if (addr != NULL)
{
printf ("error: %s: found symbol \"no_such_symbol\"\n", name);
abort ();
}
const char *message = dlerror ();
if (message == NULL)
{
printf ("error: %s: missing error message\n", name);
abort ();
}
const char *message_without_path = strchrnul (message, ':');
if (strcmp (message_without_path, expected_message) != 0)
{
printf ("error: %s: unexpected error message: %s\n", name, message);
abort ();
}
free (expected_message);

message = dlerror ();
if (message != NULL)
{
printf ("error: %s: unexpected error message: %s\n", name, message);
abort ();
}
}

static void
test_handles (const char *name, void *(func) (void *, const char *),
const char *suffix)
{
test_one (RTLD_DEFAULT, name, func, suffix);
test_one (RTLD_NEXT, name, func, suffix);

void *handle = dlopen (LIBC_SO, RTLD_LAZY);
if (handle == NULL)
{
printf ("error: cannot dlopen %s: %s\n", LIBC_SO, dlerror ());
abort ();
}
test_one (handle, name, func, suffix);
dlclose (handle);
}

static void *
dlvsym_no_such_version (void *handle, const char *name)
{
return dlvsym (handle, name, "NO_SUCH_VERSION");
}

static void *
dlvsym_glibc_private (void *handle, const char *name)
{
return dlvsym (handle, name, "GLIBC_PRIVATE");
}

static int
do_test (void)
{
test_handles ("dlsym", dlsym, "");
test_handles ("dlvsym", dlvsym_no_such_version,
", version NO_SUCH_VERSION");
test_handles ("dlvsym", dlvsym_glibc_private,
", version GLIBC_PRIVATE");

return 0;
}


#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"

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